大多数RBC体积很小，并且缺乏中部苍白的区域，是球形红细胞。在遗传性球形红细胞增多症中，因红细胞膜骨架蛋白缺乏，故膜通透性增加，从而导致细胞处于球形。在实验室中，可见渗透脆性增加。球形红细胞的寿命缩短。
The size of many of these RBC's is quite small, with lack of the central zone of pallor. These RBC's are spherocytes. In hereditary spherocytosis, there is a lack of spectrin, a key RBC cytoskeletal membrane protein. This produces membrane instability that forces the cell to the smallest volume--a sphere. In the laboratory, this is shown by increased osmotic fragility. The spherocytes do not survive as long as normal RBC's.
